Bobbin stripping unit

ABSTRACT

A bobbin stripping unit for removing yarn residues from a bobbin, the bobbin being substantially cylindrical with a longitudinal axis. The bobbin stripping unit includes a holding device which holds the bobbin in a substantially vertical or horizontal position with respect to its longitudinal axis, at least one suction nozzle extending over substantially the entire length of the bobbin for sucking in yarn residues, and a casing which can be transferred between a stripping configuration and a release configuration. In the stripping configuration, the casing substantially surrounds the bobbin, at least partially. In the release position, the casing exposes the bobbin for insertion and removal.

The present invention relates to a bobbin stripping unit for removing yarn residues from a bobbin, the bobbin being substantially cylindrical with a longitudinal axis, comprising a holding device which holds a bobbin in a substantially vertical or horizontal position with respect to its longitudinal axis, at least one suction nozzle extending over substantially the entire length of the bobbin for sucking in yarn residues, and a casing which can be transferred between a stripping configuration and a release configuration, the casing in the stripping configuration surrounding the bobbin at least partially, preferably substantially completely, and in the release position exposing the bobbin for insertion and removal.

In the following, the term “bobbin” also refers to a roving bobbin and, more generally, any type of substantially cylindrical device carrying a yarn, a thread, a stubbing or roving wound thereon. Such bobbins are also referred to as tubes and must be freed from yarn residues after unwinding of the yarn before being used again. To date, essentially three different basic designs are known for the purpose of stripping bobbins, i.e. for removing yarn residues from these bobbins.

On the one hand, manual stripping stations are known for such bobbins, in which they are placed on manual stripping stations and rotated there. In this case, the wound roving or yarn has to be inserted by hand. This means that there are considerable staff costs for operating such stations. However, automatic stripping stations are also known in which the bobbins stand upright and rotate, in this state a small tube with a venturi nozzle or a vacuum travels along the bobbin to find the roving or yarn. Thus in such stations, suction is only applied selectively and the entire stripping process is relatively time-consuming. In addition, if the roving or yarn breaks, a new search process is necessary during which the bobbin often unwinds and spreads the yarn or roving yarn in the station.

Finally, alternative automatic stripping stations are also known in which a hollow tube is guided over the bobbins to be stripped from above until it surrounds them completely. Compressed air is then blown into the tube from below and the air is extracted upwards by a fan. In this case, the bobbin is not rotated or otherwise moved during the stripping process. Although such stations can be operated relatively quickly and cost-effectively, the stripping results are often unsatisfactory as the yarn is not always adequately broken up. Furthermore, such stations are relatively bulky and, particularly in designs with a plurality of stripping units in which a plurality of bobbins can be stripped, are also expensive to purchase.

It is therefore the object of the present invention to provide an improved generic bobbin stripping unit which eliminates the disadvantages of the prior art and is characterised by reliable and efficient operation. This object is achieved according to the invention by providing the suction nozzle laterally next to the bobbin, extending over substantially its entire length, in cooperation with the casing surrounding the bobbin at least partially, but for example also substantially completely, as a result of which excellent stripping results are achieved at the same time as cost-effective operation.

For this purpose, in the bobbin stripping unit according to the invention, the casing can be formed in several parts and the plurality of parts of the casing can be displaced substantially along directions which are oriented substantially perpendicular to the longitudinal axis of the bobbin, which is held by the holding device, for transferring between the stripping configuration and the release configuration. Thus, the plurality of parts of the casing in the bobbin stripping unit according to the invention are brought close to the bobbin to be stripped from the outside, which enables a higher number of stripping process cycles and a higher throughput of bobbins compared with the stripping unit described above in which a tube is slipped over the bobbin from above. In addition, the removal of yarn residues is more reliable as the suction nozzle can extend over the entire length of the bobbin, whereas as described above, in the known stripping stations, suction can only take place upwards through the tube or via the small tube on the side with the venturi nozzle or the vacuum.

Alternatively, however, similarly to as is known from prior art, the casing could also be slipped over the bobbin using suitable means in order to move it into its stripping configuration, even in such an embodiment the arrangement of the suction nozzle laterally next to the yarn reel would provide the advantages according to the invention described above.

The casing in its stripping configuration can have at least one opening, for example between at least two adjacent parts of its plurality of parts, to allow the air necessary or sucking up the yarn residues to circulate around the bobbins in an optimum manner. Alternatively or additionally, the openings could of course also be provided in the parts themselves in the form of holes or slots.

Particularly in the case where the at least one opening is provided between at least two adjacent parts of the plurality of parts of the casing, the one opening or at least one of the plurality of openings can extend over substantially the entire length of the bobbin along its longitudinal axis. In this way, it is possible to ensure that yarn residues located in all positions on the bobbin can be effectively sucked in. Furthermore, in cases where a plurality of openings is provided, they can also be arranged one above the other and/or offset from each other and/or along the longitudinal axis of the casing.

In an exemplary embodiment, the casing can be formed by two half shells which each cover an angular range of approximately 180°. The two half shells can then be moved towards each other around the bobbin to be stripped until they surround the bobbin substantially concentrically in the stripping configuration. It is evident that, even with such half shells, at least one opening can be provided in the casing formed by these half shells such that, for example, one of the two half shells can cover an angular range which is slightly less than 180°, while the other covers exactly 180°, so as to form the opening mentioned as a result of the angular range which is missing from the full 360°. In general, however, it is possible to split the angles, which can extend up to approximately 90° to 270°, between the two half shells, it evidently being possible that an opening can remain with such asymmetrical embodiments.

In an advantageous embodiment, the or at least one of the suction nozzles can be assigned to one of the plurality of parts of the casing. Consequently, in such a case, the suction nozzle can be displaced together with the corresponding part in order to transfer it mutually between the release position and the stripping position. This ensures that the relevant nozzle is always optimally positioned in relation to the bobbin to be stripped.

Alternatively or additionally, the or at least one of the suction nozzles is assigned to a displacement device which is configured to displace the at least one suction nozzle substantially parallel to the longitudinal axis of the bobbin which is held by the holding device. In this way, the suction nozzle can be displaced to its working position independently of the casing, for example from above or below in the case of bobbins arranged vertically for stripping.

In a development of the present stripping unit, the at least one suction nozzle can have a narrowing in the flow direction of the suction. At this narrowing, the flow speed of the air sucked in is increased selectively so that, for example, a roving at this point can be broken up.

Although the bobbins to be stripped in the bobbin stripping unit according to the invention and also the suction nozzle can each be positioned fixedly relative to each other, it can be advantageous, to ensure a satisfactory stripping result, if either the holding device is configured to rotate the bobbin it holds about its longitudinal direction or if the at least one suction nozzle is provided with a rotation device which is configured to rotate the suction nozzle about the bobbin which is held by the holding device, its rotational axis coinciding substantially with the longitudinal axis of the bobbin. In this context, it should again be pointed out that the suction nozzle can be moved towards the bobbin from the side or, if the bobbin is completely encased, from below. It is possible with both of the embodiments mentioned to ensure that yarn residues located in all circumferential positions of the bobbin to be stripped are reliably removed.

To parallelise the bobbin stripping process and be able to strip a plurality of bobbins simultaneously in a coordinated manner, the present invention also relates to a bobbin stripping arrangement, comprising a plurality of bobbin stripping units according to the invention, a control unit being provided which is configured to operate the plurality of bobbin stripping units in a coordinated manner. In this way, even further synergy effects can be achieved beyond the pure time gain due to parallelisation, for example by using a single device to generate the vacuum necessary for suction for a plurality of the bobbin stripping units used in parallel.

Finally, the present invention relates to a method for operating a bobbin stripping unit according to the invention, comprising the steps:

-   -   Providing the casing in its release position;     -   Transferring a bobbin which is held by the holding device to a         designated working position;     -   Transferring the casing to its stripping configuration, in which         it substantially completely surrounds the bobbin arranged at the         working position;     -   Operating the at least one suction nozzle according to         predetermined parameters for sucking in yarn residues located on         the bobbin;     -   Transferring the casing to its release position again; and     -   Removing the bobbin which is held by the holding device from the         working position.

Further features and advantages of the present invention become apparent from the following description of two embodiments if they are considered together with the accompanying figures. These show in detail:

FIGS. 1a-1d a first embodiment of a bobbin stripping unit according to the present invention in four different views; and

FIGS. 2a and 2b a second embodiment of the present invention in two different views with minimal and complete encasement respectively.

In FIGS. 1a to 1d , a first embodiment of a bobbin stripping unit according to the invention is denoted in each case by the reference number 10. Here, FIGS. 1a and 1c show the stripping unit 10 in its release position in each case and FIGS. 1b and 1d show the stripping unit 10 in its stripping configuration in each case. In particular, FIGS. 1a and 1b present top views of the stripping unit 10, the viewing direction running along the longitudinal axis L of the bobbin S which may, for example, be arranged standing upright. FIGS. 1c and 1 d, on the other hand, show the bobbin stripping unit 10 and the bobbin S in a lateral view in each case.

As can be seen from FIGS. 1a to 1 d, the bobbin stripping unit comprises two half shells 12 and 14 which are spaced apart in the release configuration and are in contact with each other in sections in the stripping configuration and form a substantially circular overall cross-section which, as can be seen in FIG. 1b , is aligned substantially concentric with the longitudinal axis L of the bobbin S. It should be mentioned at this point that various other cross-sections of the casing are conceivable, for example polygonal, such as rectangular or square cross-sections, or even oval-shaped cross-sections.

As can also be seen in FIG. 1b , the first half shell 12 extends over a full 180°, while the second half shell 14 extends over a slightly smaller angular range such that an opening 16 also remains in the stripping configuration through which the air can flow into the interior of the casing. Again, it should be remembered that the angular range covered in each case by the two half shells could also differ from 180°, and in particular could be in the entire range from 90° to 270°.

On the other hand, the air flowing through this opening 16 is sucked away from the bobbin S by a suction nozzle 18, which is assigned to the first part 12 of the casing, and which also extends over the entire height of the bobbin S, any yarn residues remaining on the bobbin S being removed during this suction process. The vacuum required to operate the suction nozzle 18 is generated here by a vacuum source, not shown, which is connected to the nozzle 18 using suitable conducting means.

In the embodiment shown in FIGS. 1a to 1d , the bobbin S is held rotatably by the holding device such that it is rotated by said device about its longitudinal axis L, as a result of which the stripping action of the suction nozzle 18 can be exerted evenly over the entire circumference of the bobbin S.

In contrast, FIGS. 2a and 2b show an embodiment of a bobbin stripping unit which is denoted by the reference number 10′ and which comprises a nozzle 18′ rotating about the longitudinal axis L of the bobbin S, while the bobbin S itself is held non-rotationally. For reasons of clarity, FIGS. 2a and 2b do not show the two parts 12 and 14 of the casing; however, they are constructed and can be operated in the same way as those in FIGS. 1a to 1 d. 

1. A bobbin stripping unit for removing yarn residues from a bobbin, wherein the bobbin is substantially cylindrical with a longitudinal axis, wherein the bobbin stripping unit comprises: a holding device which holds the bobbin in a substantially vertical or horizontal position with respect to its longitudinal axis; at least one suction nozzle extending over substantially the entire length of the bobbin for sucking in yarn residues; and a casing which can be transferred between a stripping configuration and a release configuration, wherein the casing in the stripping configuration surrounds the bobbin at least partially and in the release position exposes the bobbin for insertion and removal.
 2. The bobbin stripping unit according to claim 1, wherein the casing is formed in a plurality of parts that are displaceable towards and away from the bobbin substantially along directions which are oriented substantially perpendicular to the longitudinal axis of the bobbin, which is held by the holding device, for transferring between the stripping configuration and the release configuration.
 3. The bobbin stripping unit according to claim 1, wherein transferring the casing into the stripping configuration comprises slipping the casing over the bobbin.
 4. The bobbin stripping unit according to claim 1, wherein the casing in the stripping configuration has at least one.
 5. The bobbin stripping unit according to claim 4, wherein the at least one opening extends over substantially the entire length of the bobbin.
 6. The bobbin stripping unit according to claim 1, wherein the casing is formed in two half shell parts which each cover an angular range of approximately 180°.
 7. The bobbin stripping unit according to claim 1, wherein the casing comprises a plurality of parts that are displaceable towards and away from the bobbin substantially along directions which are oriented substantially perpendicular to the longitudinal axis of the bobbin; and wherein the at least one suction nozzle is assigned to one of the plurality of parts of the casing.
 8. The bobbin stripping unit according to claim 1, wherein the at least one suction nozzle is assigned to a displacement device which is configured to displace the at least one suction nozzle substantially parallel to the longitudinal axis of the bobbin (S) which is held by the holding device.
 9. The bobbin stripping unit according to claim 1, wherein the at least one suction nozzle has a narrowing in the flow direction of the suction.
 10. The bobbin stripping unit according to claim 1, wherein the holding device is configured to rotate the bobbin about its longitudinal axis.
 11. The bobbin stripping unit according to claim 1, wherein the at least one suction nozzle is provided with a rotation device which is configured to rotate the suction nozzle about the bobbin which is held by the holding device, wherein the rotation device rotates around a rotational axis that coincides substantially with the longitudinal axis of the bobbin.
 12. A bobbin stripping arrangement, comprising: a plurality of bobbin stripping units, wherein each of the bobbin stripping units comprises: a holding device for holding a bobbin in a substantially vertical or horizontal position with respect to a longitudinal axis of the bobbin, a suction nozzle extending over substantially the entire length of the bobbin for sucking in yarn residues, and a casing which can be transferred between a stripping configuration and a release configuration, wherein the casing in the stripping configuration surrounds the bobbin at least partially and in the release position exposes the bobbin for insertion and removal; and a control device configured to operate the plurality of bobbin stripping units in a coordinated manner.
 13. A method for operating a bobbin stripping unit, wherein the bobbin stripping unit comprises a holding device for holding a bobbin in a substantially vertical or horizontal position with respect to a longitudinal axis of the bobbin, at least one suction nozzle extending over substantially the entire length of the bobbin for sucking in yarn residues, and a casing which can be transferred between a stripping configuration and a release configuration, the method comprising the steps: providing the casing in the release position; when the casing is in the release position, transferring a bobbin held by the holding device to a designated working position; when the bobbin is arranged at the designated working position, transferring the casing to the stripping configuration, in which the casing substantially surrounds the bobbin; when the casing is in the stripping configuration, operating the at least one suction nozzle to suck in yarn residues located on the bobbin; upon completing operation of the at least one sucking nozzle, returning the casing to the release position; and when the casing is returned to the release position, removing the bobbin which is held by the holding device from the working position.
 14. The bobbin stripping unit according to claim 1, wherein the casing in the stripping configuration substantially completely surrounds the bobbin.
 15. The bobbin stripping unit according to claim 1, wherein the at least one opening is located between at least two adjacent parts of the plurality of parts of the casing.
 16. The bobbin stripping unit according to claim 1, wherein the casing is formed in a plurality of parts that are displaceable substantially along directions which are oriented substantially perpendicular to the longitudinal axis of the bobbin for transferring between the stripping configuration and the release configuration; and wherein the at least one suction nozzle is assigned to one of the parts of the casing such that transferring the casing into the stripping configuration displaces the at least one suction nozzle to be substantially parallel to the longitudinal axis of the bobbin.
 17. The bobbin stripping arrangement of claim 12, further comprising a vacuum device connected to the nozzle of each bobbin stripping unit; and wherein the control device is configured to operate the vacuum device to generate a vacuum necessary for sucking in the yarn residue through each nozzle in parallel. 